We wish to study the structure and transcription of intracellular SV40 chromosomes in order to understand the relationship between chromosome structure and the control of gene transcription in eukaryotic cells. We plan to investigate the possibility that non-histone cellular or viral encoded proteins bind to SV40 chromosomes and thereby determine the specificity of transcription. The possibility that these proteins bind to specific sites on SV40 DNA will be investigated by using restriction endonucleases and a novel binding assay designed to detect nanogram amounts of material. The nucleotide sequence of protein binding sites on SV40 DNA detected in this manner will be determined. The distribution of histone and non-histone proteins on SV40 DNA will be studied using restriction enzymes and non-specific nucleases as probes and by the direct visualization of the DNA-protein complexes in the electron microscope. The RNA associated with SV40 chromosomes in vivo and the RNA synthesized from the chromosomes in vitro by endogenous and purified RNA polymerases will be characterized by RNA-DNA hybridization studies. If the in vivo specificity of transcription is maintained in vitro, reconstitution studies will be undertaken to identify and purify the components involved. One of the fundamental problems in biology is the understanding of the mechanism of the control of transcription in eukaryotic organisms. It is hoped that the experiments proposed here will advance this understanding.